Lowitz arcs

Lowitz arcs were first observed by Tobias Lowitz in 1790. Ever since, these arcs have been observed by numerous observers ( 1 ). These particular arcs were photographed on February 19 in Finland.

Halo Meeting 2009

There is less than half a year left until Halo Meeting 2009. The "official" registration form ( 1 ) has been added to our website, and also important information about the costs and the method of payment. Please, read these pages carefully, fill in the form, and keep it in mind that the deadline for both registering and paying the fee is 31 May 2009. You will notice that our homepage has moved to a new address – this is due to regular problems with the previous server ( 2 ).

We are looking forward to hosting this event very much.

More light on spatial halos

Streetlamp halos with their spatial form can be memorable experiences for the viewer. Yet, we know rather little of them. But now this is changing as Walt Tape has taken a look at several spatial halos in four articles ( 1 ). There are numerous revolutionary insights and a whole new nomenclature is created. And best of all, articles can be read also by mathematically less gifted as there are hardly no equations.

44 parhelia in Estonia

On 3rd of January it was possible in South-Estonia, Tartu to observe bright halo what was photographed by many people and was later reflected by media. Afterwards I was browsing the news ( 1 ) on ilm.ee and noticed that there might be 44° parhelion in picture taken by Aavo Omann ( 2 ). After closer inspection and browsing other captures it was clear that indeed it was 44° parhelion because there were no signs of 46° lateral arcs and the 22° upper tangent arc was weak.

Halo display in Himos on the night of 2/3 February

On the evening and night of 2-3 February 2009, I was testing my new HID-spotlight that I finally got earlier on that same day. What would be better place for testing than nearby Himos ski resort in Jämsä, Finland. After being there for a few hours and seeing nothing but 22° halo with my lamp, I decided to go home. Luckily, at the same time, the sky started to clear and I first saw a half moon and Parry arc on that. Then I noticed also 46° halo and quickly took a few pictures and started heading back closer to Himos where I found a place to set up my camera and lamp. I stayed on that same location all the time, because there was some wind and things may change quickly.

Lamp elevation was about 2 or 3 degrees. Haloes were supralateral arc, parhelic circle, Wegener, subhelic, suncave Parry, Parry supralateral, 46°halo, Tricker, Greenler, "Ounasvaara arc" ( 1 ) (first observed by Marko Riikonen -07) and more. Temperature was between -7 to -10 C. See a few pictures and videos ( 2 ).

Stacking a snow surface halo

Above is a comparison of snow surface halo stacked from 40 frames two different ways (click image for an animation). The photo on the right with crystal glitter is hand-stacked with Photoshop using Lighten-method, which was introduced by Piikki in the early winter ( 1 ). The other photo is stacked automatically with Registax. Because of the crystal glitter, Lighten-method provides more realistic output, though of course this is much enhanced realism.

Camera was moved between every shot some 30 cm sideways. 24° halo is well visible in 148 frame mirrored stack ( 2 ). Pyramidal crystals were observed with microscope, but unfortunately I could not get them photographed. The display was photographed on 30 January in Tampere, on Näsijärvi ice.

Bright Tricker arcs in Prichovice

On 10 January 2009, Jan Smejkal observed a complex display in Prichovice, in which some rarer halo forms - such as the anthelion brightened by crossing Tricker arcs - were in action, too. The more frequent halo arcs included suncave and sunvex Parrys, Wegener, a faint helic, upper Tape arcs and subhelic arc ( 1 – 2 – 3 – 4 – 5 – 6 – 7 ). The photos also show a weak Liljequist parhelion ( 8 ).

Jan Smejkal described the weather during the complex halo in the following way: "On 10 January 2009, Prichovice was slightly above inversion, and time to time some very thin clouds crossed the sun. The display was observed at different intesities from around 9:00 until 11:30UTC when the sun got covered by clouds."

More information on the Czech diamond dust displays can be found in some articles at the following site: ( 9 ).

Text: Martin Popek and Matej Grek